SPEAR is the acronym for the European research project Seismic PErformance Assessment and Rehabilitation of existing buildings, and the SPEAR building is the three-storey replica of an existing non-seismic building, full-scale tested at the ELSA Laboratory. The building was intended as representative of the southern European construction practice of the ¿60s and ¿70s, and the mock-up was built by reproducing materials and detailing of that period. The most interesting feature was the presence of a number of sources of structural irregularity, resulting into a 10% in-plan eccentricity.
The mock-up was pseudodynamically tested as subjected to a bidirectional seismic input. The test sequence included a series of tests on the structure in its original configuration as well as in two conceptually different rehabilitated configurations. The first configuration corresponded to the attempt of increasing the global available ductility by increasing the confinement in all the potential plastic hinge zones, and was practically enforced by use of FRPs. The other configura-tion aimed at reducing the torsional response, which had been found responsible for a large percentage of the total interstorey deformation. This was done by concrete-jacketing a limited number of columns, so to re-locate the centre of strength in the vicinity of the gravity centre.
Whereas the first method proved to be somehow more effective in terms of structural behav-iour, an assessment of the two different solutions is sought in terms of life-cycle cost-benefit analysis.
Based on the results of the testing activities, and reverting to the real building, the cost-benefit analysis is carried out for the two rehabilitation measures and the two solutions are compared. The method represents a rational basis for deciding upon the best rehabilitation measure, and could be extended to take into account environmental issues.